This study aimed to generate a GIS-based flashflood hazard susceptibility map using the geographical information system (GIS) and frequency ratio (FR) techniques in one of the geographically isolated and disadvantaged areas (GIDAs) of the country, which is the barangay Bukang… More

This study aimed to generate a GIS-based flashflood hazard susceptibility map using the geographical information system (GIS) and frequency ratio (FR) techniques in one of the geographically isolated and disadvantaged areas (GIDAs) of the country, which is the barangay Bukang Liwayway of Kibawe, Bukidnon. There are 160 sample points conducted for flashflood inventory to calculate FR and the flashflood prediction weights values needed to generate the flashflood susceptibility map. The elevation, slope, aspect, curvature, topographic wetness index, drainage density, LULC, normalized difference vegetation index, and rainfall are the nine controlling factors that are selected. Results show that the areas exposed to flashflood with low, medium, and high-risk levels of susceptibility consist of 89.8, 4.4, and 5.7% of the total land, respectively, with 25 households exposed to high risk. The study determined the possible site for the evacuation center based on the spatial analysis resulting in the overlaying of different thematic map layers based on flashflood susceptibility factors. The study emphasizes the integration of the findings in the localized comprehensive land-use plan to realize the challenge of building a sustainable and hazard-resilient human community in Bukang Liwayway. Less

Flooding is one of the most devastating natural disasters in the Philippines, especially in Mindanao. This study aimed to generate datasets of flooding along the Gingoog River based on Geographic Information System (GIS). The method employed simulation and mapping of… More

Flooding is one of the most devastating natural disasters in the Philippines, especially in Mindanao. This study aimed to generate datasets of flooding along the Gingoog River based on Geographic Information System (GIS). The method employed simulation and mapping of flood hazards using the Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) and the HEC-River Analysis System (HEC-RAS) within the GIS environment. Rainfall data on December 15, 2015, with a total amount of 20.8 mm and peak discharge of 43.49 m3s-1, were used to simulate flood hazards. The model was calibrated, and its accuracy was tested, and after which, its overall evaluation showed a satisfactory performance, implying applicability to simulate floods during extreme rainfall events. Using Light Detection and Ranging (LiDAR) data, flood maps of the three return periods were generated within HEC-RAS. Results showed that flooding extended up to 2.965 km2, 4.165 km2, and 5.040 km2 with maximum flood depths of 7.77 m, 8.12 m, and 8.49 m for 5-year, 25-year, and 100-year return periods, respectively. The model, together with the hydrologic behavior of the watershed such as the extent of flooding, is very helpful for the development and enhancement of early warning systems in the affected areas. Less